The background description provided here is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
A cooling system for an engine typically includes a radiator, a coolant pump, an inlet line, and an outlet line. The inlet line extends to an inlet of the engine from an outlet of the radiator. The outlet line extends from an outlet of the engine to an inlet of the radiator. The coolant pump circulates coolant through the inlet line, the engine, the outlet line, and the radiator. In some cases, the cooling system includes a bypass valve that allows coolant to bypass the radiator when the bypass valve is open.
An engine control system typically controls coolant flow through the engine by adjusting the speed of the coolant pump. Conventional engine control systems adjust the coolant flow to minimize the difference between a desired coolant temperature and a measured coolant temperature. Controlling coolant flow in this way may be referred to as a feedback approach.
Controlling coolant flow using only the feedback approach may be adequate during steady-state conditions, such as when a vehicle is traveling at a constant speed. However, controlling coolant flow using only the feedback approach may not adjust the coolant temperature as quickly and as accurately as desired during transient conditions, such as when a vehicle is accelerating.